Improve comment syntax suggestions

[sambostock]

This adds handling for <%- #, and clarifies that <%#= is just a comment starting with =, as opposed to some special construct.

Original	Replacement	Notes
<% #	<%#
<%= #	<%#	If the = was there unintentionally, it can be removed.
<%= #	<%#=	If temporarily commenting out the line, with the intent of restoring it.
<%- #	<%-#	- affect whitespace, so we it should be kept, even if this is a comment.